Overload release clutch



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OVERLOAD RELEASE CLUTCH Filed May 4, 1946 2 Sheets-Sheet l jme/Moz @www @gua fRmomP/v/vass www@ jm Wm April 25, 1950 B. P. PlNKvoss OVERLOAD RELEASE CLUTCH 2 Sheets-Sheet 2 Filed May 4, 1946 xr Wald BERN/ULD PvP/kwas Patented Apr. 25, 1950 UNITED STATES *PATENT G'FFICE `22,505,742 OYEBLQAD RELEASE, CLUTCH Berthold VI. Binkvoss, Stratford, Conn., assignor to The Singer Manufacturing Company, -Elizabeth, N. J., a corporation of New Jersey firrliootioo Mor 4, 19456, Serial No. .667,265

l1-Claims. 1

This invention relates to overload release clutches, and more particularly to a type of clutch that is especially adapted, though not neearily restricted, for use in a high speed sewingmachine similar to the one disclosed in a United States patent application, Serial No. 641,233, led January 15, 1946, now Patent Number 2,425,120 by Frank Parry and Berthold P. Pinkvoss.

Overload release clutches have been used eg;- tonsvely for disconnecting the rotary hook from the main drive when the rotary hook becomes jammed or inoperative, thereby to prevent breakage of sewing machine parts. A clutch of `this type is disclosed in the United States patent of W. A. Andres, No. 11,914,795, June 2Q, 193,2. -ln prior constructions, little consideration `-had been given to producing a clutch with a spring that could be adjusted with ,the optimum ease and aecuracy. Furthermore, the prior art indicates that no consideration had been given to providing a low inertia overload release clutch suitable 'for use in present day high speed sewing machines which are subjected to periods ,of rapid acceleration and deceleration.

Therefore, one object of the present invention is to provide anew and improved overload release .Clutch having a spring that can be adjusted easily and accurately.

Another object of the invention is to provide a new and improved low inertia overload release clutch that is especially adapted for use in high speed sewing machines. A

Further important objects oi the invention will be apparent from the iollcwing detailed description and appended claims. f

For a completeunderstanding olf the invention, reference should be made to the accompanying drawings, wherein:

Fig. l is a longitudinal vertical sectional view of a high speed sewing `machine embodying the `present invention;

Fig. 2 is a View taken along the line 2.-. 2 of Eig. 1 and looking in the direction of the arrows; the members beine rotated from the Position Shown in Fig. 1.

Fig. 3 is a View Vtalsan alone tho 3-f-f3 of Fig. 1 and looking in the directionof thearrows the clutch members being disengaged and rotated from that shown in Fig. 1.

Fig. 4 is a sectional view taken substantially along the line 4-4 of Fig. 2, and looking in the direction of the arrows;

Fig. 5 is an enlarged view oi `a. portion `of the mechanism shown in Fig. 2;

minertia overload release clutch 2l.

Fig. 6 is a View similar to Fig. 5, but showing ,Parts diorontly adjusted; and

Fig. 7 `is a sectional view taken substantially alors the ,liner-1 of Fig 5' l'tfeferring more specifically to the drawings, the invention isdisclosfed asapplying to a sewing machine having a frame comprising abed ill and a Ybra cket-armI l2, the latter having a vertically disposed standard |3, supported by the bed Irl, and ,a 'horizontally disposed overhanging arm 14, carriedon the upper end of the standard I3. The left end o the arm Ill is -formed into a bracketarm hood "i Ar pair of bearings -Il and 18, positioned in `opposite ends of the arm l2, rotatably supports a Ahcrizontally disposed `needle-bar actuating shaft i9. The-shaft AIll carries, at its rightrend (Fig. `l), a combination belt and hand wheel 2| which has ail-shaped annular groove 22 adapted to receive a driving `belt `23. The left endof the shaft drives `liereinafter mentioned mechanisms that are carried in the bracket-arm head I6. The shaft 19, at a point intermediate of its ends and above `the standard 13, carries a small diameter 19W inertia pulley 24 which through alclip belt 25 drives, in one-to-one ratio, a small diameter low A drivingpulley element 28 of the clutch 2l drives 'la rotatable sleeve 29, being secured thereto by set screws 3L vAdriven hub-element 32 of the clutch 2-1 drives a rotatable shaft 33, being secured there- `to by setscrewsv3ll (Fig. e). The elements 28 and `32 are-coaXially-positoned with respect to one` another, and are `releasably,corn-rooted for unison rotation. The shaft 33 is 4concehtrically carried within the sleeve 29, and the two are supported ina manner hereinafter described.

The mechanisms supported in the bracket-arm head I6 include a springpressed presser-bar 36 and a reciprocatory, vibrator-y needle-bar 37 having apair of needles 38. `lt/iechanism for reciprocating and vibrating the needle-bar, as wellfas an upper eccentric mechanism Sil Afor varying the vbratory-moven-ient of the needle-bar 31, is driven from the hereinbefore mentioned shaft I9. 'A pair of loop-takers (not shown) and a four motioned lower feeding mechanism il are housed below `the bed l l. AThe loop-takers may be of any one o f nseveral `known types and are driven atla two-to-one ratio from the shaft 33 by a pair of Vgears -(not shown). The feeding mechanism, which has a `pair oineedleopenings 42, is driven through an adjustable eccentric mechanism 43 irom'the sleeve 29. A means `for simultaneously and synchronously varying the eccentricity of the upper eccentric mechanism 39 and the lower feed-drive eccentric 43 is designated by the numeral 44. It will be understood that the movement of the feeding mechanism 4i and its needle openings 42 will always be maintained in synchronism with the vibratory movement of the needle-bar 31 and the needles 38. It will also be understood that under normal operating conditions the loop-takers (not shown) will cooperate with the needles 38 to form two lines of stitches.

A lug 45 depending from the bed Il supports the outer race ring of a ball bearing 41, the inner race ring of which rotatably supports the right -end (Fig. l) of the sleeve 23. A second lug 48 also depending from the bed H carries a bearing bushing 43 which rotatably supports the shaft 33. The right end of the sleeve 28 rotatably supports the right end of the shaft 33 by means of a bearing portion 51, and the sleeve 29 is rotatably supported on the shaft 33 by a bearing portion 52.

As hereinbefore mentioned, the pulley element 28 of the clutch 21 is secured to and rotates with the sleeve 29. The right face of this element carries a toggle joint 53 (Figs. 2 and 3) having an arcuate link 54 which is pivotally held in place by a screw 56. Intermediate the ends of the link 54 a wedge-shaped projection 51 extends inwardly from the concave side of the link. The link 54 is pivotally connected to one end of a toggle-link 58 by a pin 53, whereas the other end of the toggle-link 58 carries a pin 8|, to which is pivotally connected one end of a rst arm 62 of a bow spring 83. The two-armed bow spring 53 is fulcrumed at a point intermediate of its ends on a pin or screw 64. In the embodiment illustrated, the fulcrum pin or screw 64 is threaded into and projects from the side face of pulley element 28. A second arm 88 of the bow spring extends beyond the screw 84 and is engaged by a head 51 of a pin 68, the pin being located on the inner sid-e of said arm 66, at a point substantially diametrically opposite the pin 6I. In other words the bow spring 63 is semicircular in form and substantially embraces the driven element 32. The head 61 is eccentrically formed as an integral part of a stem 83 which is disposed for turning adjustment in 9, hole 1I provided in the pulley element 28. A set screw 'i2 may be screwed into or out of a threaded hole 13 thereby to engage or disengage the stem 69.

A pawl 14 is pivotally mounted on the pin 59 and has a hooked portion 18. One end of a coiled spring 11 is supported in a hole 18 formed in the clutch element 28. The other end of the spring engages a pin 19 carried by the pawl 14 and the spring thereby biases the pawl toward the hub 32. The periphery of the driven clutch element 32 is provided with two recesses 81 and 82. The recess 8| is wedge shaped and is designed for engagement by the wedge-shaped projection 51 of the link 54. The second recess 82 is provided with a shoulder 83 for engag-ement by the hooked portion 15 of the pawl 14.

In order to prevent turning of the shaft 33 and its driven clutch element 32 when performing an operation hereinafter described, there is provided a disk 84 (Fig. 1) which is secured to the shaft 33 by a set screw 86. A hole 81, provided in the periphery of the disk, may be engaged by a manually operated and spring retracted pin 88 that is carried by the bed I l. Y

In operation, the hereinbefore described pulley sleeve 29 ar-e driven in a clockwise direction as indicated by the arrow 8S of Fig. 2. Under normal conditions the hub 32 and therefore the l shaft 33 are likewise driven in a clockwise direction due to the engagement of the projection 51 with the recess 8l. When, however, an excessive load is applied to the shaft 33, the wedge-shaped projection 51 is forced out of the recess 8l and, due to a slight reverse bending of the toggle, the wedge-shaped projection 51 of the link 54 is moved and held in a position (Fig. 3) out of contact with the hub 32. Then, due to the spring 11, the free end of the pawl 14 is caused to ride freely over the periphery of the hub 32 in a clockwise direction as long as the driving element 28 overruns the driven element 32.

When it is desired to re-estalolish driving relation between the driving member 28 and the hub 32, the operator stops the sewing machine and depresses the pin 88. vrIhen, by manual operation of the hand wheel 2|, the clutch element 2S and thus the pawl 14 are rotated in a counterclockwise direction (arrow 9|, Fig. 3) until the hoo-k po-rtlon 15 of the pawl engages the shoulder 83 on the driven element 28. This causes the shaft 33 to rotate until it is stopped by pin 88 entering hole B1. Further movement of the hand wheel 2| and the element 23 applies force to the pin 59 and breaks the toggle thereby causing the projection 51 to enter the recess 81.

In the event that it becomes desirable to regulate the stress under which the projection 51 will be forced out of the recess 8i, it is simply necessary to adjust the biasing eifect of the bow spring 53 by turning adjustment of the eccentric pin 58. Turning of the pin to one position (Fig. 5) moves the eccentric and the arm 53 away from the center of the clutch element 28 and thereby tightens the spring and the toggle; whereas turning of the pin S8 to another position (Fig. 6) allows the arm 86 to move toward the center of the clutch element 28 and thereby decreases the effect of the bow spring 53. The eccentric pin 68 is held in any desired adjusted position by means of the set screw 12.

Due to the novel shape, positioning and arrangement of parts hereinbefore described, this invention has provided an easily adjustable overload release clutch of small diameter and low inertia. Overload release clutches having these characteristics have been found to be especially useful for use with modern type high speed sewing machines.

Having thus set forth the nature of the invention, what I claim hereinl is:

l. An overload release clutch having a rotatable driving element, a rotatable driven element, means for connecting said elements comprising members pivoted to form a toggle joint, a bow spring having two resilient arms, a fuicrum pin for pivotally mounting said bow spring and located intermediate said two arms, and a spring adjusting mechanism; one of said arms of the bow spring being pivotally connected to one of said toggle members and the other of said arms being engaged by the spring adjusting mechanism at a point remote from said fulcrum pin.

2. An overload release clutch having a rotatable driving element, a rotatable driven element, members pivoted to form a toggle joint, a projection carried by at least one of said elements, and the other of said elements being provided with a recess arranged for engagement by said projection and thereby connecting said elements, a bow spring having two resilient arms, an adjustable eccentric pin, and means for holding said pin in an adjusted position; one of said arms of said bow spring being pivotally connected to one of said toggle members, and the other of said arms being engaged by the eccentric pin.

3. An overload release clutch having a rotatable driving element, a rotatable driven element, means for connecting said elements comprising members pivoted to form a toggle joint, a resilient bow spring semicircular in form and substantially embracing one of said elements, a fulcrum pin for pivotally mounting said bow spring and located intermediate the two ends of said spring and thereby defining two resilient arms, and an eccentric adjusting mechanism; one of said resilient arms being connected to said toggle joint and the other of said resilient arms being engaged by said eccentric mechanism at a point remote from said fulcrum pin.

4. An overload release clutch having a rotatable driving element, a rotatable driven element, a separable connection between said driving element and said driven element, and means for adjustably biasing said connection; said means for adjustably biasing said connection, comprising, a resilient bow spring semicircular in iorrn and having an inner concave side adjacent and substantially embracing one of said elements, one end of said bow spring being linked to a -portion of said separable connection; and an eccentric pin so constructed and arranged as to adjustably engage the inner concave side of the other end of said bow spring.

BERTHOLD P. PINKVOSS.

REFERENCES CITED The following references are of record in the 1 le of this patent:

UNITED STATES PATENTS Number Name Date 1,914,795 Andres June 30, 1933 20 2,003,115 Grohn May 28, 1935 2,256,781 Nelson Sept. 23, 1941 

